halftone block meaning in Hindi

Examples

1. The use of halftone blocks in popular journals became regular during the early 1890s.
2. Frederic E . Ives is usually credited with the first commercially successful process that was compatible with ordinary letterpress printing, so that halftone blocks could be printed along with blocks of text in books, periodicals and newspapers.
3. A lack of skill in graphic arts and photo-processes resulted in ruined print illustrations .  At that time, only a few local firms like Thacker and Spincks ( of Thacker's Indian Directory ) took commercial orders for halftone blocks but they were very costly.